Conventional plowing devices typically incorporate a metal moldboard that has been pre-formed into a desired shape according to the intended use of the plowing device. In some instances, it is desirable to use a metal moldboard that is formed into a side discharge configuration as shown in U.S. Pat. No. 4,045,892 granted to Farrell while in others, it is desirable to use a moldboard that is pre-formed into a dual side discharge configuration as shown in U.S. Pat. No. 4,459,769 granted to Willis. Sr. Since the metal moldboards are preformed, however, the metal moldboards must be repeatedly interchanged according to the conditions of the surfaces needing plowing. For example, a street may require the plowing of snow to the right side of the street while the moldboard mounted on the vehicle is configured to move the snow only to the left. The time required to switch the left discharge moldboard with a right discharge moldboard is highly undesirable since the vehicle is removed from service during such changeover.
The metal moldboards also present other problems of economics. For example, forming the metal moldboards into a desired configuration requires a laborious bending process during fabrication which adds significantly to the moldboard cost. Additionally, since the moldboards are composed of metal, the weight of the plowing device is quite heavy thus significantly detracting from the efficient fuel consumption of the plowing vehicle.
It has been known to avoid some of the problems associated with the use of pre-formed metal moldboards by instead using a plastic moldboard as shown in U.S. Pat. No. 4,837,951 issued to Verseef. In the device disclosed in the Verseef patent, undesirable downtime of the vehicle due to changing of a moldboard is avoided since the same moldboard may be selectively oriented in either a right, left or intermediate discharge position. Specifically, the Verseef patent discloses a plastic moldboard that may be selectively formed into a desired configuration by the vehicle operator according to the actuation of a plurality of hydraulic cylinders. The formation of the moldboard into the desired configuration is completely separate from any other operation of the plow.
While the device disclosed in the Verseef reference may offer improvements in operating costs over the operating costs associated with pre-formed metal moldboards, the Verseef device suggests a complexity that is likely to increase upfront purchase costs. The Verseef device also utilizes a number of operating mechanisms that are likely to degrade plow reliability as well as contribute to excessive maintenance downtime. For example, to arrange the plastic moldboard into a desired orientation, the Verseef device requires the simultaneous actuation of two dual acting hydraulic cylinders that must be supported by an appropriate hydraulic valving apparatus. Should such a hydraulic system fail, the usefulness of selectably orienting the plastic moldboard would be disabled.
Further, the Verseef device retains the plastic moldboard within the plow framework in a manner that may decrease the operating life of the plastic moldboard. In particular, the plastic moldboard in the Verseef device is attached to the plow framework in part by two baseplates that fail to allow the plastic moldboard appropriate freedom of movement during orientation of the moldboard. Since the moldboard is restricted from movement, undesirable stresses will be repeatedly induced in the plastic moldboard during orientation thus decreasing the useful life of the moldboard.
Yet still further, the Verseef device utilizes a scraper blade that apparently is attached to the lower portion of the plow by commonly known fasteners. As is commonly known within the art, extended use of a scraper blade causes the fasteners to become corroded thus hampering efforts to replace the scraper blade when necessary. The fasteners may become so corroded as to fail during attempted removal. Such detractions during replacement efforts of the scraper blade, increase the amount of valuable time a vehicle may be unavailable for plowing use.
In view of the above, it is an object of the present invention to provide an improved plowing device which is readily capable of selective discharge of the plowed material.
A further object of the present invention is to provide a plowing device of high reliability and low complexity.
It is a further object of the present invention to provide a plowing device requiring low maintenance.
It is a further object of the present invention to provide a plowing device capable of selectively changing the discharge direction of a moldboard in response to pivoting of the plowing device.
Another object of the present invention is to provide a plowing device having a scraper blade that is easily replaceable.
Yet a further object of the present invention is to provide a plowing device capable of selective discharge orientation with a flexible moldboard having increased useful life.
An additional object of the present invention is to provide a plowing device capable of easily bypassing obstacles located on a plowed surface without causing damage to the plowing device.
The above objects as well as other objects not specifically enumerated are accomplished by a plowing assembly in accordance with the present invention. The plowing assembly of the present invention includes a cross-beam and a moldboard assembly. A first forming rib is disposed at one end portion of the cross-beam and has a first device for retaining a first upper corner portion of the moldboard assembly. A second forming rib is disposed at an opposite end portion of the cross-beam and has a second device for retaining a second upper corner portion of the moldboard assembly. The assembly also includes first and second actuating devices for pivoting the cross-beam around a pivot point such that the first and second forming ribs conform the moldboard assembly into a desired shape.